From 7e42ccdaf21a2e10ffc4af11f56f84ee97d41c5b Mon Sep 17 00:00:00 2001
From: Thomas Lamprecht <t.lamprecht@proxmox.com>
Date: Wed, 22 Jul 2020 17:46:02 +0200
Subject: [PATCH] fixed index: chunk_from_offset: avoid slow modulo operation

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
---
 src/backup/fixed_index.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/backup/fixed_index.rs b/src/backup/fixed_index.rs
index 59f63d2e..5d6cc1ff 100644
--- a/src/backup/fixed_index.rs
+++ b/src/backup/fixed_index.rs
@@ -212,7 +212,7 @@ impl IndexFile for FixedIndexReader {
 
         Some((
             (offset / self.chunk_size as u64) as usize,
-            offset % self.chunk_size as u64
+            offset & (self.chunk_size - 1) as u64 // fast modulo, valid for 2^x chunk_size
         ))
     }
 }